Submission #534639

#	Time	Username	Problem	Language	Result	Execution time	Memory
534639		perchuts	Pipes (CEOI15_pipes)	C++17	30 / 100	1109 ms	63760 KiB

pipes

#include <bits/stdc++.h>
#define maxn (int)(1e5+51)
#define all(x) x.begin(), x.end()
#define sz(x) (int) x.size()
#define endl '\n'
#define ll long long
#define pb push_back
#define ull unsigned long long
#define ii pair<int,int>
#define iii tuple<int,int,int>
#define inf 2000000001
#define mod 1000000007 //998244353
#define _ ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);

using namespace std;

template<typename X, typename Y> bool ckmin(X& x, const Y& y) { return (y < x) ? (x=y,1):0; }
template<typename X, typename Y> bool ckmax(X& x, const Y& y) { return (x < y) ? (x=y,1):0; }

int lvl[maxn], par[maxn], lvl2[maxn], par2[maxn], dp[maxn], lvl3[maxn];
bool vis[maxn];

int findp(int x){return par[x] = (x==par[x]?x:findp(par[x]));}
bool merge(int x,int y){
    int a = x, b = y;
    x = findp(x), y = findp(y);
    if(x==y)return 0;
    if(lvl[x]<lvl[y])swap(x,y);
    par[y] = x;
    lvl[x] += lvl[y]==lvl[x];
    return 1;
}

int findp2(int x){return par2[x] = (x==par2[x]?x:findp2(par2[x]));}
bool merge2(int x,int y){
    int a = x, b = y;
    x = findp2(x), y = findp2(y);
    if(x==y)return 0;
    if(lvl2[x]<lvl2[y]){
        swap(x,y);
    }
    par2[y] = x;
    lvl2[x] += lvl2[y]==lvl2[x];
    return 1;
}
vector<int>g[maxn];

void dfs(int u,int p){
    vis[u] = 1;
    for(auto v:g[u]){
        if(lvl3[v]==0){
            lvl3[v] = lvl3[u]+1;
            dfs(v,u);
            dp[u] += dp[v];        
        }else if(lvl3[v]<lvl3[u])dp[u]++;
        else dp[u]--;
    }
    dp[u]--;
    if(dp[u]==0)cout<<u<<" "<<p<<endl;
}

int main(){_
    int n,m;cin>>n>>m;
    for(int i=1;i<=n;++i)lvl[i] = lvl2[i] = 0, par[i] = par2[i] = i;
    for(int i=0;i<m;++i){
        int a,b;cin>>a>>b;
        if(merge(a,b)){
            g[a].pb(b);g[b].pb(a);           
        }else if(merge2(a,b)){
            g[a].pb(b);g[b].pb(a);           
        }
        }
    for(int i=1;i<=n;++i)
        if(!vis[i])dfs(i,i);
}

Compilation message (stderr)

pipes.cpp: In function 'bool merge(int, int)':
pipes.cpp:25:9: warning: unused variable 'a' [-Wunused-variable]
   25 |     int a = x, b = y;
      |         ^
pipes.cpp:25:16: warning: unused variable 'b' [-Wunused-variable]
   25 |     int a = x, b = y;
      |                ^
pipes.cpp: In function 'bool merge2(int, int)':
pipes.cpp:36:9: warning: unused variable 'a' [-Wunused-variable]
   36 |     int a = x, b = y;
      |         ^
pipes.cpp:36:16: warning: unused variable 'b' [-Wunused-variable]
   36 |     int a = x, b = y;
      |                ^

• Subtask 1: 10 / 10
• Subtask 2: 0 / 10
• Subtask 3: 10 / 10
• Subtask 4: 0 / 10
• Subtask 5: 0 / 10
• Subtask 6: 10 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10
• Subtask 10: 0 / 10